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The following archive was created by hippie-mail 7.98617-22 on Thu May 27 1999 - 23:44:20
Greg Rose (ggr@qualcomm.com)
Tue, 06 Apr 1999 08:13:12 +0100
Two things have struck me as funny about this whole thread. The first is
that it is virtually identical to the path taken only a few months ago in
convincing Mok-Kong Shen that there's a reason for using (and
understanding) standard terminology... and there were postings by Mr. Alten
at the same time. If he wasn't betting his company on it, I'd say he was
trolling.
The other is that nobody else seems to have picked up on his other huge
gaffe, perhaps because ones-complement arithmetic has been out of fashion
for a long time now... Guess I'm showing my age.
At 00:19 2/04/99 -0800, Alex Alten wrote:
>In practice the "+" is ones complement addition, i.e. an exclusive OR
>operation.
(For the young at heart, "ones complement" represents negative numbers as
the bitwise complement of the corresponding positive number, so that
0xFF...FF is "minus zero". Signed addition involves wrapping the carry bit
back around. It has some advantages in gates, but complicates software no
end. It does not implement addition with XOR. What we now (almost
universally) use is called "twos complement representation".)
Greg. (who continues work on OFB mode stream ciphers, which are decidedly
breakable, but getting better.)
Greg Rose INTERNET: ggr@Qualcomm.com
Qualcomm Australia VOICE: +61-2-9181-4851 FAX: +61-2-9181-5470
Suite 410, Birkenhead Point, http://people.qualcomm.com/ggr/
Drummoyne NSW 2047 232B EC8F 44C6 C853 D68F E107 E6BF CD2F 1081 A37C
The following archive was created by hippie-mail 7.98617-22 on Thu May 27 1999 - 23:44:20